H-alkanes

Baldauf, H., Scoen.Herr, J., and Schubert, H., Alkane Dicarboxilic Acids and Amino Naphthol-Sulphonic Acids - a New Reagent Regime for Cassiterite Flotation, International Journal of Mineral Processing, Vol. 15, pp. 117-133, 1985. 

Veith, H.J. Gross, J.H. Alkane Loss From Collisionally Activated Alkylmethyle-neimmonium Ions. Org. Mass Spectrom. 1991,26, 1061-1064. 

RP Hjelm, P Thiyagarajan, H Alkan-Onyuksel. Organization of phosphatidylcholine and bile salt in rodlike mixed micelles. J Phys Chem 96 8653-8661, 1992. 

Demos, S.M., H. Alkan-Onyuksel, B.J. Kane, K. Ramani, A. Nagaraj, R. Greene, M. Klegerman, and D.D. McPherson, In vivo targeting of acoustically reflective liposomes for intravascular and transvascidar ultrasonic enhancement. J Am Coll Cardiol, 1999. 33(3) 867-75. 

One of the most popular nitroxide-based radicals (TEMPO) has been shown to abstract H-atoms from activated C—H bonds. However, the nitroxide itself is easily photo-degraded, hi order to examine more photochemically stable alternatives to TEMPO in abstraction reactions, the related isoindoline nitroxide radical (61) has been examined.116 Abstractions from unactivated primary, secondary, and tertiary C—H alkane bonds were all achieved. 

However, this simple model does not explain the (kinetically) enhanced reactivity of arenes relative to alkanes, considering the higher (Dc-h) bond energy of arenes, i.e. Dc-h, benzene — 111 lccal mol-1 vs. Dc-h,alkane 95 lccal mol-1. Many more examples of metal-activated cleavage of C-H bonds are known for aromatic compounds than for alkanes [37]. To account for this difference, arene/metal coordination is proposed [38], although experimental evidence for such intermediate complexes and their structural features is lacking. 

Single bonded compounds R3C-H Alkane R3SDH Silane... 

A curious thermodynamic result is connected to the cohesive energy of an ionic liquid. From calorimetric experiments, performed to determine the heat of vaporization along an homologous family of cations, the increment in enthalpy of vaporization per -CH2- group was calculated [25] and it closely matches that observed for the H-alkanes, suggesting that, in the ionic liquid phase, the alkyl chains exist in an alkane-like environment. 

Armstrong [32] showed that stationary phases composed of ionic liquids could be used to separate polar compounds and, unexpectedly, that their resolving power for the series of H-alkanes was high, demonstrating the dual nature of the ionic liquids, interacting both with polar and nonpolar compounds. 

A hydrocarbon that contains only single bonds is an alkane (general formula C H2 +2, where n is a positive integer). For example, if n = 5, the formula is C5H[(2x5)+2] or C5H12. The alkanes comprise a homologous series, one in which each member differs from the next by a —CH2— (methylene) group. In an alkane, each C is sp hybridized. Because each C is bonded to the maximum number of other atoms (C or H), alkanes are referred to as saturated hydrocarbons. 

For example. Burger et al. (1981) characterized an oil sample composed of 14% wax, 58% of which included hydrocarbons in the range and Barker (1995) noted that microcrystalUne waxes in a refined petroleum sample was composed of 20-40% H-alkanes, 15-40% wo-alkanes and 35% cycloalkanes. The HMWHCs in the 40. region are of particular interest since they are thought to be the primary culprit in wax deposition problems. Case studies have demonstrated that a minimal microcrystalline wax content of 2% in an oil can result in wax deposition problems (Holder Winkler 1965 Tuttle 1983 Ajienka Ikoku 1990). 

We begin the discussion on deaminations of open-chain amines with the only case in which the rate-limiting step is the formation of the alkanediazonium ion. This brings us to the evaluation of compounds in which the amino group is attached to C(l) of an -alkane. Two relatively recent investigations of Fishbein s and Kirmse s groups (Hovinen and Fishbein, 1992 Brosch and Kirmse, 1991), using diazotization kinetics of methylamine and the deamination products of two stereochemically pure 1-amino [1- H] alkanes, respectively, elucidated clearly fundamental problems of... 

From the i.r. readout, the characteristic C-H alkane absorption is present at 2800 cm . The sharp, symmetric absorption at 1380 cm indicates the presence of either i methyl or ethyl but not an isopropyl or t-butyl group. 

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